Typical inkjet printing apparatus discharge ink from nozzles provided in printing heads to print an image on a printing medium. In each inkjet printing apparatus, printing heads provided with nozzle openings have nozzle surfaces facing the printing medium and discharge ink at an appropriate timing while the printing heads is moving relative to the printing medium.
A printing medium improperly disposed on a conveying surface, in particular, a printing medium leaving the conveying surface results in the contact of the printing medium with various portions of the inkjet printing apparatus to damage a nozzle surface or being trapped in a printing head or a head unit provided with the printing head(s) (collectively referred to as an “image former”) or in a frame, causing a jam. To cope with this problem, techniques are used to stop printing an image upon occurrence of such a problem or upon detection of a possibility thereof and move the image former to remove the problematic printing medium. PTL 1 discloses techniques to stop conveyance of the printing medium upon detection of a lifting printing medium and then move the image former to a retraction position. PTL 2 discloses techniques to ascend or separate the image former disposed in the vicinity of the conveying surface upon detection of a lifting printing medium in accordance with the uplift level or stop conveying the printing medium.
PTL 3 discloses techniques to prevent attachment of contaminant to a printing medium supporting surface (platen) by preventing exposure thereof when the supporting surface is separated from an image former to remove a jammed printing medium.